1. Field of the Invention
The present invention relates to a nitride semiconductor light emitting device.
2. Description of the Related Art
In recent years, a group III-V nitride semiconductor, such as a GaN semiconductor, has been prominent as an essential material for light emitting devices, such as light emitting diodes (LEDs), laser diodes (LDs), and the like, due to its excellent physical and chemical properties. LEDs or LDs using a group III-V nitride semiconductor material are mainly used in light emitting devices for producing light in a blue or green wavelength band. These light emitting devices are being used as light sources for various applications requiring high current and high output such as backlight units (BLUs), electronic display boards, lighting apparatuses and the like.
With the use of a nitride semiconductor light emitting device in various applications, a method of effectively injecting electrons into an active layer has become important in a high-power light emitting device having a large area. According to the related art, a super lattice layer has been stacked for the diffusion of current into the active layer and for stress relief, and an electron ejection layer has been grown for electron injection. However, such a complex stack structure may increase stress and the possibility of occurrence of defects in an interface, and defects may be propagated to the active layer, whereby light emitting efficiency and reliability of the semiconductor light emitting device may be reduced.